taxonomy_description=Hematology+%26+Oncology.
No auth required. result_count=200 means the page cap was hit; the true total is higher.
Raw data: npi-counts-oncology.json ·
Memphis raw ·
Wyoming raw ·
Script: npi-counts-oncology.ps1
taxonomy_description=Hematology+%26+Oncology as your primary string.
Then run Medical+Oncology and Hematology separately and merge all three.
"Oncologist" returns zero. A single oncology string captures at most one-third of the workforce.
taxonomy_description=Oncologist returns 0 results.
The oncology workforce is not a single taxonomy — it fragments across three primary strings:
Hematology & Oncology, Medical Oncology, and Hematology.
Each returns 200+ records nationally. A rep querying "Oncology" alone also captures every oncology
subspecialty (Radiation Oncology, Gynecologic Oncology, Surgical Oncology) — a different problem
of over-inclusion. There is no single query that captures exactly "the oncologists in my territory."
This page shows how to build the complete picture.
Queried 2026-06-13 using taxonomy_description=Hematology+%26+Oncology.
"200+" means the 200-record page cap was hit; true totals are higher.
| Market | Records returned | Notes |
|---|---|---|
| New York, NY | 200+ | Capped — significant concentration at academic centers |
| Los Angeles, CA | 200+ | Capped |
| Chicago, IL | 200+ | Capped |
| Houston, TX | 200+ | Capped — includes MD Anderson area providers |
| Nashville, TN | 200+ | Capped — Vanderbilt cancer center drives density |
| Phoenix, AZ | 79 | Complete count for city proper |
| Memphis, TN | 97 | Complete count — see drill-down below |
| Vermont (statewide) | 73 | All providers statewide |
| Wyoming (statewide) | 31 | Low density — use statewide, not by city |
Source: npi-counts-oncology.json, queried 2026-06-13.
207RH0003X — Internal Medicine, Hematology & Oncology (the main pool)207RX0202X — Internal Medicine, Medical Oncology207RH0000X (via related match) — Pediatric Hematology-Oncology174400000X — Specialist (various non-physician roles)enumeration_type=NPI-1.
The CMS NUCC taxonomy separates oncology physicians across multiple strings. Each returns substantial national data. Querying only one string misses the others entirely.
| Taxonomy string | NUCC code | National sample (2026-06-13) | Notes |
|---|---|---|---|
Hematology & Oncology |
207RH0003X | 200+ (capped) | Primary string — Internal Medicine subspecialty; largest oncology pool nationally |
Medical Oncology |
207RX0202X | 200+ (capped) | Separate IM subspecialty certificate; significant additional providers |
Hematology |
207RH0000X | 200+ (capped) | Hematologists who also treat malignancies; relevant for most oncology products |
Gynecologic Oncology |
207VG0400X | 200+ (capped) | Separate specialty under Obstetrics & Gynecology — not in IM query |
Surgical Oncology |
2086S0102X | 200+ (capped) | Surgical subspecialty — separate from medical oncology |
Pediatric Hematology-Oncology |
2080P0207X | 200+ (capped) | Pediatrics subspecialty — separate parent taxonomy |
Oncologist |
N/A | 0 results | Not a CMS taxonomy code — returns zero |
Source: npi-counts-oncology.json, queried 2026-06-13.
These are your primary physician pool — internal medicine subspecialists who deliver systemic cancer therapy:
# String 1 — the largest pool
https://npiregistry.cms.hhs.gov/api/?version=2.1
&taxonomy_description=Hematology+%26+Oncology
&city=Memphis&state=TN&limit=200
# String 2 — additional Medical Oncology-certified providers
https://npiregistry.cms.hhs.gov/api/?version=2.1
&taxonomy_description=Medical+Oncology
&city=Memphis&state=TN&limit=200
# String 3 — hematologists relevant to most oncology portfolios
https://npiregistry.cms.hhs.gov/api/?version=2.1
&taxonomy_description=Hematology
&city=Memphis&state=TN&limit=200Gynecologic Oncology, Surgical Oncology, and Pediatric Hematology-Oncology each have separate NUCC codes. If your indication covers any of those patient populations, they need their own query passes.
A provider board-certified in both Hematology & Oncology and Medical Oncology can appear in both result sets.
The NPI number is the deduplication key — it is unique per provider nationally.
Filter enumeration_type=NPI-1 to isolate individual physicians from organizations.
Oncologists concentrate at cancer centers and academic hospitals. In mid-size metros (Memphis, Phoenix), 25 miles captures most of the metropolitan area. In rural states (Wyoming: 31 statewide), query by state rather than city — the call list is small enough that geography is not the binding constraint.
Oncology is a moderately concentrated specialty — practices anchor around hospital cancer programs and infusion centers, not spread evenly across the metro like primary care.
For rural territories, a rep should combine Wyoming and surrounding states (Colorado, Montana, Idaho, Utah) into separate queries rather than trying to capture multi-state geography in a radius.
"Oncologist" is a professional title, not a CMS taxonomy code. The NPI registry uses NUCC taxonomy strings —
the correct primary string is Hematology & Oncology (207RH0003X). The ampersand and exact spacing
are required; the API returns zero for "Oncologist", "Oncology" alone, or any variation.
At minimum three: Hematology & Oncology (207RH0003X), Medical Oncology (207RX0202X),
and Hematology (207RH0000X). Each returns 200+ records nationally. If your territory covers surgical
oncology or gyn onc, add Surgical Oncology and Gynecologic Oncology as separate queries.
A single-string approach leaves most of the call list on the table.
Both describe internal-medicine subspecialists who treat cancer with systemic therapy, but they are distinct NUCC taxonomy codes. Hematology & Oncology (207RH0003X) is the more common board-certification path combining both disciplines. Medical Oncology (207RX0202X) is a narrower subspecialty certificate. In practice both groups see the same pharmaceutical and device reps, so both strings belong on your call list.
No. Gynecologic Oncology and Surgical Oncology are separate NUCC taxonomy strings and return their own records. A Hematology & Oncology query will not capture them. If your product is indicated for surgical or gyn-onc contexts, those strings require their own query passes and a deduplication merge.
Wyoming statewide returned 31 Hematology & Oncology records on 2026-06-13 versus 97 in Memphis city alone. Oncology concentrates at academic medical centers and cancer centers in urban markets. In rural states, oncologists cluster in one or two cities; patients often travel 100+ miles to major centers. A Wyoming rep should query statewide rather than by city and should also run Hematology and Medical Oncology separately.
Memphis returned 15 NPI-2 organization records (cancer centers and oncology group practices) alongside
individual physician NPI-1 records in the Hematology & Oncology query. Organization records contain group
addresses and phone numbers but not individual physician names. For a call plan, filter by
enumeration_type=NPI-1 to isolate individual providers. Use organization records separately for
institutional account planning — they represent the group practice or cancer center as a billing entity.